Implantable cardiac rhythm management (CRM) systems, including pacemakers, implantable cardioverter/defibrillators (ICDs), and cardiac resynchronization therapy (CRT, CRT-D) devices have been used to deliver effective treatment to patients with serious cardiac arrhythmias. In particular, rate adaptive pacing systems are known which utilize data obtained from various implantable sensors, e.g., activity sensors such as accelerometers and minute ventilation sensors, to adjust pacing parameters in response to increased patient demand. Despite significant technological advances in rate adaptive pacing technologies in recent years, there exists a continuing need for improved pacing systems and methods, particularly for use in patients suffering from congestive heart failure (CHF).